I can't speak to the Underjams question, but have bought from Jet a few times. I didn't understand their game until recently, basically trying to be another Amazon by stocking some items themselves and outsourcing other items to partners. My last order consisted of supplements, office supplies, and a movie. The first two came in a bright purple Jet-labeled box, but the movie came from DeepDiscount.com. Exactly what arrives will depend on either Jet's internal policies or the partner's policies. If you're buying less than a case, I don't think there's any reason for concern. For cases...err, yeah, I suspect only the better incontinence/medical suppliers make a commitment to unmarked boxes.